England VS Australia T20I: Why did Jos Buttler not appeal for Matthew Wade's obstruction?

Wade was yet to score and had just joined David Warner (unbeaten on 73) with the Aussies on track to chase down England's 6-208 when he top-edged a scorching bouncer from Mark Wood into his helmet in the 17th over.

As a dazed Wade regained his composure, he made several strides down the crease only to be sent back by Warner, the ball ballooning straight into the air at the striker's end.

When Wood attempted to complete the caught and bowled, Wade threw out his left arm, making contact with the England speedster's chest as he dived to get back into his ground, with the ball dropping within the crease around a meter from the stumps.

Buttler and Wood both stood with their arms raised briefly before opting not to appeal for obstructing the field, and the game continued after a doctor evaluated Wade for concussion.

What is Law 37 of the MCC Laws of Cricket?

1. Obstruction of the field

Either batsman has been dismissed. If he intentionally obstructs or distracts the fielding side through words or behaviour, he is blocking the field. Furthermore, it shall be considered an obstruction if, while the ball is in play, either batsman strikes the ball with his bat or person, other than a hand not holding the bat, after a fielder has touched the ball. This applies whether or not the fielding side is at a disadvantage. 

2. Accidental obstruction

It is up to either umpire to determine whether an obstruction or distraction is intentional. If he is unsure, he should consult the other umpire.

3. Obstructing a ball from being caught

The striker is out if either batter causes a deliberate obstruction or distraction that prevents a catch from being made. This applies even if the striker causes the impediment while lawfully guarding his wicket per Law 34.3. (Ball lawfully struck more than once).

While it would have been up to third umpire Phil Gillespie to assess if Wade intentionally blocked Wood had England appealed, no judgment was required. The left-hander went on to knock 21 from 15 balls before being removed on the fourth last delivery of the match as the hosts fell eight runs short of a record T20 international chase in Australia.

Buttler said after the game that he was so concentrated on the ball that he didn't notice the contact between Wade and Wood.

Although it is a rare dismissal, the two teams have had similar incidents in the past.